Blow Back problem

Donny Bear · #1 09-21-2008, 07:07 AM

Cat Dick you out there hello anyone

I have my boys Tika T3 300wsm load works good for accuracy sub MOA
but the residue from blow back on the case is crazy I have seated the bullet as far ahead as I can and have the cartridge still fit in the clip and I am still 50 thou of the lands. I have ordered a neck re-sizing die as I am convinced that the chamber on this rifle is large the spent brass will not chamber in my 300wsm. So I think that it would be better not to re-size the cartridge just the neck. Do you think I am on track or could I be doing something else? The brass and primers are showing no evidence of excess pressure. I have never seen this amount of residue. I am using Varget for the first time in the 300wsm but have used it in small bore with no such effect I realize some say the powder is to fast for a magnum cartridge but the loads are out of the manual and they are accurate

bobinthesky · #2 09-21-2008, 07:34 AM

I could be wrong but I doubt that neck sizing only will make any difference, the brass of the neck still has to expand to fill the chamber and make a seal. If you're chamber is oversize, then the brass will work harden quickly and you won't get much life out of your brass regardless of whether you use a neck size die or full length. I know you said that you like the Varget but have you tried a different powder? Possibly a slightly slower powder may give the brass a little more time to expand and fill the chamber resulting in less blow by. On the other hand, if you're not getting blow by in the action, then why worry about it?

Unregistered user · #3 09-21-2008, 08:20 AM

Do you have this problem with factory ammo?

Donny Bear · #4 09-21-2008, 08:30 AM

Never fired factory Ammo from this gun but did experiance similar results not quite so bad with Reloader 22 but the groups were groady

1.30 to 1.70 @ 100m that was over 4 gr at .5 increments.

Case life is not a huge concern

Donny Bear · #5 09-21-2008, 08:38 AM

2" group at 200m with the Varget

spurly · #6 09-21-2008, 08:42 AM

I would try a different powder first, some powders are just plain dirtier than others.Is the blowback only on the neck or does it go down onto the shoulder area as well. Depending on how far down you have your sizing die adjustedyou may be pushing the shoulder backa thou or two to far, this could result in headspce problems,and would be first noticeable by slightly protuding primers.If you have the instructions from your dies, it will explain how to adjucst for full and neck sizing. there is also info available in the internet about how to smoke a case in order to get optimumshoulder contact.

Dick284 · #7 09-21-2008, 09:23 AM

Since I know your running slightly reduced loads in the lads 300WSM, this is likely your culprit. Reduced pressures result in a slowed response in the case to expanding fully into the chamber, as well as probably resulting in a bit of incomplete ignition of the propellent, which in turn results in a dirtier than normal burn.
You have to remember that you are doing some pretty un conventioanl stuff with this caliber, and as they say "there is no such thing as a free lunch."

Bobby B. · #8 09-21-2008, 09:39 AM

For what it's worth, I set my FL sizer to neck size only my 7RM cases and there is no powder residue on the cases. I have a NS die for my 6/284 and there is powder residue on the cases. I'm not convinced sizing is the culpirt in your case. My 7RM VLD's seat .010" into the lands and the 6/284 BT seat at the lands. Hope this helps.

Bobby B.

Pathfinder76 · #9 09-21-2008, 09:47 AM

You're not running at the pressures that you should be.

Donny Bear · #10 09-21-2008, 11:45 AM

Quote:

Originally Posted by Dick284

Since I know your running slightly reduced loads in the lads 300WSM, this is likely your culprit. Reduced pressures result in a slowed response in the case to expanding fully into the chamber, as well as probably resulting in a bit of incomplete ignition of the propellent, which in turn results in a dirtier than normal burn.
You have to remember that you are doing some pretty un conventioanl stuff with this caliber, and as they say "there is no such thing as a free lunch."

Good point Dick I guess I will change out the The CCI bench primers go to a Mag primer to up ignition and see if a cleaner hotter ignition will help. Lots of stuff to ponder here

Thanks Guys

Huntnut · #11 09-22-2008, 09:01 AM

Quote:

Originally Posted by Dick284

Since I know your running slightly reduced loads in the lads 300WSM, this is likely your culprit. Reduced pressures result in a slowed response in the case to expanding fully into the chamber, as well as probably resulting in a bit of incomplete ignition of the propellent, which in turn results in a dirtier than normal burn.
You have to remember that you are doing some pretty un conventioanl stuff with this caliber, and as they say "there is no such thing as a free lunch."

I ran into the same thing with my 7mm rum when I first got it and was working up loads-when I started 10% below listed max. I would get what you are getting.

bobinthesky · #12 09-23-2008, 09:05 AM

I didn't realize you were using reduced loads of Varget in your son's .300wsm... Thats a big no no in over bore cases and in my opinion, you're playing with fire. Lots of rifles have been blown up that way over the years. I'd change to a slower powder that fills the case before you have bigger problems than just dirty brass! Switching to a hotter primer is not the answer.

Donny Bear · #13 09-23-2008, 09:29 AM

Quote:

Originally Posted by bobinthesky

I didn't realize you were using reduced loads of Varget in your son's .300wsm... Thats a big no no in over bore cases and in my opinion, you're playing with fire. Lots of rifles have been blown up that way over the years. I'd change to a slower powder that fills the case before you have bigger problems than just dirty brass! Switching to a hotter primer is not the answer.

The Loads are by no means that reduced and the cases are at 90% thanks for the heads up everything I have done to this point has been based on solid research again I am seeing no eveidence of excess pressure on the case which would show or atleast should show

bobinthesky · #14 09-23-2008, 10:27 AM

Quote:

Originally Posted by Donny Bear

The Loads are by no means that reduced and the cases are at 90% thanks for the heads up everything I have done to this point has been based on solid research again I am seeing no eveidence of excess pressure on the case which would show or atleast should show

Since I have no idea of your reloading experience and the fact that you gave no indication of what your load is, other than it is reduced from max, then I had to asume the worst since this can be such an unforgiving hobby. And, for what it's worth, reduced loads typically give no signs of excessive pressure before they blow up a rifle! Those are the reasons that I said what I did. I won't argue with tested data put out by the manufacturers, if you are using that. Switching to a magnum primer dosn't sound like it though.

Donny Bear · #15 09-23-2008, 11:25 AM

Quote:

Originally Posted by bobinthesky

Since I have no idea of your reloading experience and the fact that you gave no indication of what your load is, other than it is reduced from max, then I had to asume the worst since this can be such an unforgiving hobby. And, for what it's worth, reduced loads typically give no signs of excessive pressure before they blow up a rifle! Those are the reasons that I said what I did. I won't argue with tested data put out by the manufacturers, if you are using that. Switching to a magnum primer dosn't sound like it though.

Agreed and I understand no argument I appreciate the heads up. I believe you are right about the primer change I am going to go with a powder change and see what happens.